U.S. Pat. Nos. 4,734,416 and 5,006,528 discloses aripiprazole, 7-{4-[4-(2,3-dichlorophenyl)-1-piperazinyl]butoxy}-3,4-dihydro-2(1H)-quinolinone or 7-{4-[4-(2,3-dichlorophenyl)-1-piperazinyl]butoxy}-3,4-dihydro carbostyril, as an atypical antipsychotic agent useful in the treatment of schizophrenia, bipolar disease, depression and other CNS disorders. Aripiprazole has the following chemical structure:

Aripiprazole is sold under the tradename Abilify®. It acts as a dopamine D2 partial agonist, serotonin 5-HT1A receptor agonist and is an antagonist of the serotonin 5-HT2A receptor. Abilify® is currently administered orally on a once-a-day dosing schedule as Abilify® (aripiprazole) Tablets, Abilify Discmelt® (aripiprazole) Orally Disintegrating Tablets and Abilify® (aripiprazole) Oral Solution. In one embodiment, Abilify® Injection for intramuscular use is a rapid-acting solution product for treating agitation associated with schizophrenia and bipolar disease. Poor and variable patient compliance with a once-a-day dosing schedule of psychiatric drugs has been reported.
Efforts have been made to provide drug dosage forms that may increase the compliance of patients and thereby lower the rate of relapse in the treatment of schizophrenia. U.S. Pat. No. 7,807,680 and U.S. Publication No. 2005/0032811 describe long-acting aripiprazole sterile injectable formulations. Studies on aripiprazole free base injections showed a prolonged pharmacokinetic profile, but incidents of unacceptable (moderate to severe) tissue irritation following IM and SC injection were also reported.
U.S. Pat. No. 7,115,587 discloses an injectable formulation that delivers an aripiprazole solution complexed with a substituted β-cyclodextrin to the muscular site with diminished irritation as compared to injectable suspensions containing uncomplexed aripiprazole. The Abilify® injection for intramuscular use is a single-dose, ready to use vial consisting of 9.75 mg/1.3 ml of aripiprazole and 150 mg/ml of sulfobutylether β-cyclodextrin. Formulation challenges due to drug loading and poor solubility of aripiprazole in β-cyclodextrin at neutral pH have been reported.
Olanzapine (1,2-methyl-4-(4-methyl-1-piperazinyl)-10H-thieno[2,3-b][1,5]benzodiazepine) is a second generation antipsychotic drug marketed as Zyprexa®. It is useful for the treatment of disorders such as schizophrenia, bipolar disorder, psychotic depression and Tourette's syndrome. This active pharmaceutical ingredient acts as an antagonist on 5-HT2 serotonin receptors as well as the D1/D2 dopamine receptors, while also exhibiting anticholinergic and antimuscarinic properties. Olanzapine belongs to the benzodiazepine family, and has the following structure:

This compound is disclosed, for example, in U.S. Pat. Nos. 5,229,382 and 6,169,084. An extended release intramuscular injection product containing the water-insoluble salt olanzapine pamoate monohydrate is approved for use in schizophrenia. Like aripiprazole, olanzapine can cause adverse site reactions when injected into a subject.